what gears should I run in the rear ?

[stang13]

Just finishe my engine rebuild  on my 70 challenger rt .  am running a stroked 440 six pack but I have a  3.23 in the rear  so you know what that means  slow I will be using this car for local drives and cruises not planning on any highway driving . was hoping for some suggestions on what ratio to run i want this car to light the tires at the traffic light 

[Gus cuda]

Should do it now! Push a little harder on the skinny pedal on the right. 3:23's are good cruising gears for all around driving, 3:55's will give you alittle bump in performance, and 3:90's will totally change your car. Anything steeper than that will take the fun out of it I think.

[1 Wild R/T]

How big is the stroker, what cam are you running, what heads... Depending on the build 3.23's could be a good gear, strokers make torque & unless you've got good flowing heads the motor may be all done by 5500-5700 rpm's.... 3.55's, 3.73's or 3.91's could all be good choices too.. But you might be real surprised how little difference more gear will make in ET.. It'll make the car feel snappier around town but all out acceleration in a 1/4 mile often going from 3.23's to 4.10's doesn't gain you more than two tenths of a second... Yet it makes the car virtually useless for freeway driving..

[edl94]

My 440 lights up the tires with 3.23 gears.      Bonus it will cruse down the freeway at a decent RPM. It had 3.90s way to low for a big block. 3.5 is a good compramise but I like the 3.2.

[BIGSHCLUNK]

I can light em easy w 3.23's and still haul azz on the interstate...    JMHO... 

[anlauto]

3:91's

[johns cuda shop]

It really depends on your final drive ratio on the transmission and how tall your tires are.. 

[stang13]

My 440 stroker 6 pack is running an edelbrock intake and heads and a crane cam but the 323  will not light them up while I'm cruising 35 mph it will light em up tho
. the car shifts great and cruises like a Cadillac but I kida want more . is it the stall converter then?

[ToxicWolf]

Since I put a five speed trans in the car I went with 3.73s.  Take a look at your overall gearing and see what the revs will be on the highway, if you plan on cruising.   

[Chryco Psycho]

I would not change the gears , you have other issues !
 I ran a 440 duster, it ran low 12 ets in the 1/4 with 3.23 gears  , changed to 4.30s & it ran high 11s , .2 in the 1/4 , I gained more with intake swaps & general tuning !
 so you need to tune what you have , a stroked 440 should be overpowering the tires anywhere if it is  set up right !
 I drove mine about 3 miles on a fresh build unturned & lit the tires up just releasing the clutch at a light .
 You need to look at the base tuning of the engine , Timing , fuel , there is so much power in tuning , take it to a good dyno operator if you need to so ti gets diled in correctly , the problem is very few people really know how to tune & 6 pack .
 Next you could have issues with the converter / cam combo where the converter locks up before the engine is making power .You could also have internal problems with the trans eating power / not transmitting all the power through .

[stang13]

I did have this engine tuned after it was installed couldit possibly be the torque converter and gearing  / engine are miss matched . I was told that this car had a high stall converter in it ( unfortunately I dont know what rpm ) ? I did not think it was the trans because it shifts smoothly and does not slip . ( this car has a 727 torqueflight automatic in it )

[Chryco Psycho]

Hold he brakes on hard , make sure nothing is in front of you , out it into gear & hit the throttle the rpm will stop climbing at the stall speed & you can find out where the converter is stalling
Do you have the cam specs ?

[joelson6]

 

what this guy said 


i was gonna say what cam, TQ converter and rear tire size do you have.

but if you just wanna cruise, i'd leave the 3.23's

that BB should have enough torque to light the tires with 2.73's in it.

[HemiOrange70]

my almost stock 340 (PURPLE CAM, AIRGAP INTAKE AND EDDY )spins the tires with 323's

[moparmaniac59]

I've got a stroked 440 (543 cubes) and like Neil mentioned, it very much depends on the engine build, transmission and how you drive the car. I initially fried my torque convertor as it was too low a stall (2800) for the motor and gearing. I run a 3:91 rear end and a now have a 3800 stall torque convertor & yes it's stupid fast  . It tachs about 3k at 60 mph. For some folks that's too much humming for the interstate. I don't do tons of highway driving, so it does fine for me. It's a grunt motor and makes peak power at 5600 rpm. The 3:23 gears are awesome for most stock Mopars. You get into more issues with modified builds. 


                                                                                                              Matt B.